Updating bind with dynamic
A blank input line (or the send command) causes the accumulated commands to be sent as one Dynamic DNS update request to the name server.
The -d option makes nsupdate operate in debug mode.
These conditions must be met if the entire update request is to succeed.
Updates will be rejected if the tests for the prerequisite conditions fail.
Every update request consists of zero or more prerequisites and zero or more updates.
This allows a suitably authenticated update request to proceed if some specified resource records are present or missing from the zone.
The data are written in the standard text representation of the resource record's RDATA. If type and data is provided, only matching resource records will be removed.